Differential fluid and bolts??

[O Vette]

The check engine light came on and I took my '04 (with 25,000 miles) in to the dealer. The mechanic checked the codes and said there was a faulty vent valve and bad gas cap. He replaced a solenoid $25, gas cap $21, and harness $31. Add the labor of $108 and the bill was $185. Then he said he detected a noise in the back end and said GM was recommending a change to a new differential fluid and a change of the differential bolts. Said it didn't need to be done right away but, he recommended it whether he did it someone else did. Said it was important that the GM fluid be used. He reported GM has noted that this was a problem with C5's and that they reommended the new fluid. Seems strange that new bolts would have to be used. Has anyone else encountered this recommendation? This is a manual 6 speed.

 

[gkayvee]

There was a recall or service bulletin on the C5 gas filler pipe a few years ago. It was because some owners, when filling the tank had a premature shut off of the gas pump before the tank was filled. GM determined this was due to back preassure in the tank and redesigned the filler tube. Any of that sound familiar to you? I don't know anything about the rear end grease and bolts.

 

[O Vette]

I had experienced back pressure while putting fuel in and avoided that by slowing the fuel flow. I read about the service bulletin after the fix. I still don't understand the differential comments from the mechanic. I'll have to get a better explanation from him. They led me to believe it was not something that needed immediate attention so I will continue to learn more about the issue.

 

[gkayvee]

I had experienced back pressure while putting fuel in and avoided that by slowing the fuel flow. I read about the service bulletin after the fix. I still don't understand the differential comments from the mechanic. I'll have to get a better explanation from him. They led me to believe it was not something that needed immediate attention so I will continue to learn more about the issue.

Please keep me posted on what you learn about the rear. Surely if they Tech is making that kind of serious recommendation, there must be a service bulletin or recall notice about it?